A raw synthesis gas product, hereinafter called ‘unconditioned syngas’, is generated by the process of steam reforming, and may be characterized by a dirty mixture of gases and solids, comprised of carbon monoxide, hydrogen, carbon dioxide, methane, ethylene, ethane, acetylene, and a mixture of unreacted carbon and ash, commonly called ‘char’, as well as elutriated bed material particulates, and other trace contaminants, including but not limited to ammonia, hydrogen chloride, hydrogen cyanide, hydrogen sulfide, carbonyl sulfide, and trace metals. FIG. 28 presents a more complete list of components that may be found in unconditioned syngas.
Unconditioned syngas may also contain a variety of volatile organic compounds (VOC) or aromatics including benzene, toluene, phenol, styrene, xylene, and cresol, as well as semi-volatile organic compounds (SVOC) or polyaromatics, such as indene, indan, napthalene, methylnapthalene, acenapthylene, acenapthalene, anthracene, phenanthrene, (methyl-) anthracenes/phenanthrenes, pyrene/fluoranthene, methylpyrenes/benzofluorenes, chrysene, benz[a]anthracene, methylchrysenes, methylbenz[a]anthracenes, perylene, benzo[a]pyrene, dibenz[a,k]anthracene, and dibenz[a,h]anthracene.
Syngas processing technology applications can generally be defined as industrial processing systems that accept a syngas source and produce or synthesize something from it. Normally, these can be categorized into systems that generate hydrogen, ethanol, mixed alcohols, methanol, dimethyl ether, chemicals or chemical intermediates (plastics, solvents, adhesives, fatty acids, acetic acid, carbon black, olefins, oxochemicals, ammonia, etc.), Fischer-Tropsch products (LPG, Naptha, Kerosene/diesel, lubricants, waxes), synthetic natural gas, or power (heat or electricity).
A plethora of syngas processing technologies exist, each converting syngas into something, and each possessing its own unique synthesis gas cleanliness requirement. For example, a Fischer-Tropsch (FT) catalytic synthesis processing technology requires more stringent cleanliness requirements when compared to a methanol synthesis application. This is because some FT cobalt catalysts are extremely sensitive to sulfur, resulting in deactivation, whereas sulfur does not pose a problem for some catalytic methanol applications. Therefore, a vast array of permutations or combinations of syngas clean-up operational sequence steps are possible to meet the economical and process intensive demands of synthesis gas conversion technologies.